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(Mods please move this if there's a better home folder). We seem to be dominated here by testimonies about MBC timber frame and slab offerings and installations. Quite a few of the members here including me had bought an MBC frame and slab, and have nothing material other than praise. However, this shouldn't be an "I love MBC" forum, so I feel that we should really have the views and recommendations of members who have chosen another supplier, so that new members can have a range of suppliers to evaluate. I would be interested in these views.

My parents recently replaced a gas boiler that had 30 years of reliable service, could an ASHP last as long? A gas boiler+connection +some form of 'renewable' to comply may cost the same as the ASHP but maybe is more dependable? But before deciding they will have to get firm cost of installation and running costs of each. We will likely be using an ASHP simply because we have no chance of mains gas and I don't want to sell my soul to Calor.

We used Seconds and Co for PIR - however we ended up not able to use it. They sell the boards are 'x - y' sizes and therefore the luck of the draw what you get. IN our case, we got about three different type boards and 3 different thicknesses - useless for a flat roof! But for walls that will have battens or filling spaces, then ideal and a huge saving to be made. Funnily enough, I put 15 of the boards on Gumtree for £150 and could have sold them ten times over!

To clarify some details here further A red pressure vessel would be non-potable, so would relate to the primary heating circuit. The pressure gauge on that would have absolutely nothing to do with the flow rate of hot or cold water within the property. The nominal pressure for a sealed HEATING ( primary ) system would be 1-1.5 bar. That pressure would be almost identical to the gauge on the system boiler as they'd be the same body of water. Not sure what you mean here tbh. The dhw system is cold mains fed when you've got an unvented system. If you had a leak, it would hardly affect the terminal flow rate unless it was a torrent. A torrent is quite easy to find, so assume this can be ruled out. The pressure drop in a sealed heating system would only cause the boiler to switch off, and again, would leave the hot and cold flow rates completely unaffected. You need to survey the mains before recommending an accumulator. If there is insufficient static pressure, the acc would never fill, at which point ( like my current job ) you'd have to fit a break tank, a cold mains booster pump, and then the acc. Any unvented install should have a 22mm cold mains 'backbone' running throughout the house. This job has a TS, so is in essence an instant water heater. This should also have a 22mm cold mains backbone ( all cold pipework done in 22mm bar the last outlet which can be in 15mm off the 22mm ), but should also either have the majority of the hot done in 22mm, or have radial plumbing ( individual runs of small bore to each outlet from a centralised manifold ) in order to alleviate resistance from the pipework and deliver maximum flow rates. From the pics, it's clear that the plumbing may well be mostly done in 15mm. @Shell820810, do you have pics of the hot and cold connections at the TS? Also, can your hubby conform how much 22mm hot / cold pipework, if any, has been installed, and to / from where ? Ta.

Did you check that the stopcock is fully opened.

Not exactly what you are describing, but I got my insulation from 'seconds and co' who claim to be the only seller of kingspan seconds. Basically if a batch has too many flaws, Kingpan have to landfill the whole lot and these people take it off their hands for free, then bundle it up into pallets and sell it on at about a third of the normal cost. i got eighty boards this way. Two of them are closer to 40mm rather than the 50mm I require; about half a dozen more are a bit skinny but close enough that I will just use them anyway. Two have big voids within the foam, one was right at the edge and the other in the middle- you can tap the skin and play it like a drum. I will fix these using expanding foam. Many of the others have creases or slight hollows running in lines down the length of the board, where the foam filling has not fully risen (I guess they inject it from a row of nozzles about six inches apart?). Perfectly usable. And then there are the lengths of the boards, almost all are a little under 2.4m; sizes vary a lot but the majority are about 2.27m.

Ta. The connection onto the stop cock came undone a treat. All in good nick so will re-use. Duct laid in half the trench with some excess. Also brought under and up through the hole drilled in the footings. I went with a rolled bit of galv mesh to protect the duct within the suspended floor. Hopefully I won't need to get there again until I take the hall and adjacent bedroom floor up and make back into one room with en suite. One day it will all be a distant memory!

I think you'd struggle to beat the low capital and use costs of gas with an ASHP. Perversely, a poorly insulated home that can attract a higher RHI payment, may roughly draw even eventually. I'm going ASHP only because gas is not available and it's competitive compared to oil or LPG.

I like the idea MBC twin stud/slab service. But I found them to be ridiculously expensive. Most self builders use separate contractors for their foundation and timberframe, and don't have a issue.

You are trying to over complicate it. The "hot water" output of the time clock is what I normally use to control the boiler heating up the thermal store. So just that switched output and the tank thermostat on the thermal store, probably the middle one. A tank stat has quite a lot of hysteresis (unlike a room stat) so once the TS has heated up and the boiler shut off it will need to drop several degrees before the stat turns on again and calls for heat from the boiler. Yes you could have two stat's and a set / reset arrangement to give a wider hysteresis but you won't do that with all off the shelf parts. The second part is then use the heating output of the programmer, in conjunction with room thermostat(s) and zone valve(s) to turn on the pump to circulate water from the TS to the radiators or UFH. And the third part if you have a stove is an over temperature stat on the tank that turns ON when the tank gets too hot. This should override the heating programmer and rooms stats and force it to dump heat to the radiators or UFH.